Failure analysis is the forensic investigation of how and why a system or product failed. Utilizing principles of engineering, physics, and chemistry, and combining them with the inspection and testing of physical evidence, failure analysis seeks to understand the root cause of a failure and characterize it in terms of engineering specifications such as applied loads, design criteria, or material properties. Although failure analysis encompasses numerous failure modes and mechanisms, it regularly focuses on material fracture, as that is often the source of incidents such as broken pipes and chains, collapsed structures, and damaged equipment. In performing a failure analysis, numerous factors may be considered including service history, service environment, end user behavior, maintenance, and system design. Failure analysis is frequently employed in tandem with accident reconstruction and design analysis.